
package org.javaqq.face.main.base;

import sun.awt.AppContext;

import java.awt.Color;
import java.awt.Component;
import java.awt.Cursor;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Rectangle;
import java.awt.Shape;
import java.awt.event.ActionEvent;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.StringReader;
import java.io.Writer;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Enumeration;

import javax.accessibility.Accessible;
import javax.accessibility.AccessibleAction;
import javax.accessibility.AccessibleContext;
import javax.swing.Action;
import javax.swing.JComponent;
import javax.swing.JEditorPane;
import javax.swing.SizeRequirements;
import javax.swing.text.AbstractDocument;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.ComponentView;
import javax.swing.text.DefaultHighlighter;
import javax.swing.text.Document;
import javax.swing.text.EditorKit;
import javax.swing.text.Element;
import javax.swing.text.ElementIterator;
import javax.swing.text.Highlighter;
import javax.swing.text.JTextComponent;
import javax.swing.text.MutableAttributeSet;
import javax.swing.text.ParagraphView;
import javax.swing.text.Position;
import javax.swing.text.StyleConstants;
import javax.swing.text.StyledDocument;
import javax.swing.text.TextAction;
import javax.swing.text.View;
import javax.swing.text.ViewFactory;
import javax.swing.text.html.HTML;
import javax.swing.text.html.HTMLDocument;
import javax.swing.text.html.HTMLEditorKit;
import javax.swing.text.html.HTMLWriter;
import javax.swing.text.html.ImageView;
import javax.swing.text.html.MinimalHTMLWriter;
import javax.swing.text.html.ObjectView;
import javax.swing.text.html.StyleSheet;
import javax.swing.event.CaretEvent;
import javax.swing.event.CaretListener;
import javax.swing.event.HyperlinkEvent;

public class JavaQQHTMLEditorKit extends HTMLEditorKit
{

    private JEditorPane theEditor;
    
    private final JComponent container;
   
    /**
     * Constructs an HTMLEditorKit, creates a StyleContext,
     * and loads the style sheet.
     */
    public JavaQQHTMLEditorKit(JComponent container) {
    	super();
    	this.container = container;
    }

    /**
     * Get the MIME type of the data that this
     * kit represents support for.  This kit supports
     * the type <code>text/html</code>.
     *
     * @return the type
     */
    public String getContentType() {
	return "text/html";
    }


    /**
     * Create an uninitialized text storage model
     * that is appropriate for this type of editor.
     *
     * @return the model
     */
    public Document createDefaultDocument() {
	StyleSheet styles = getStyleSheet();
	StyleSheet ss = new StyleSheet();

	ss.addStyleSheet(styles);

	HTMLDocument doc = new HTMLDocument(ss);
	doc.setParser(getParser());
	doc.setAsynchronousLoadPriority(4);
	doc.setTokenThreshold(100);
	return doc;
    }

    /**
     * Inserts content from the given stream. If <code>doc</code> is
     * an instance of HTMLDocument, this will read
     * HTML 3.2 text. Inserting HTML into a non-empty document must be inside
     * the body Element, if you do not insert into the body an exception will
     * be thrown. When inserting into a non-empty document all tags outside
     * of the body (head, title) will be dropped.
     * 
     * @param in  the stream to read from
     * @param doc the destination for the insertion
     * @param pos the location in the document to place the
     *   content
     * @exception IOException on any I/O error
     * @exception BadLocationException if pos represents an invalid
     *   location within the document
     * @exception RuntimeException (will eventually be a BadLocationException)
     *            if pos is invalid
     */
    public void read(Reader in, Document doc, int pos) throws IOException, BadLocationException {

	if (doc instanceof HTMLDocument) {
	    HTMLDocument hdoc = (HTMLDocument) doc;
	    Parser p = getParser();
	    if (p == null) {
		throw new IOException("Can't load parser");
	    }
	    if (pos > doc.getLength()) {
		throw new BadLocationException("Invalid location", pos);
	    }

	    ParserCallback receiver = hdoc.getReader(pos);
	    Boolean ignoreCharset = (Boolean)doc.getProperty("IgnoreCharsetDirective");
	    p.parse(in, receiver, (ignoreCharset == null) ? false : ignoreCharset.booleanValue());
	    receiver.flush();
	} else {
	    super.read(in, doc, pos);
	}
    }

    /**
     * Inserts HTML into an existing document.
     *
     * @param doc       the document to insert into
     * @param offset    the offset to insert HTML at
     * @param popDepth  the number of ElementSpec.EndTagTypes to generate before
     *        inserting
     * @param pushDepth the number of ElementSpec.StartTagTypes with a direction
     *        of ElementSpec.JoinNextDirection that should be generated
     *        before inserting, but after the end tags have been generated
     * @param insertTag the first tag to start inserting into document
     * @exception RuntimeException (will eventually be a BadLocationException)
     *            if pos is invalid
     */
    public void insertHTML(HTMLDocument doc, int offset, String html,
			   int popDepth, int pushDepth,
			   HTML.Tag insertTag) throws
	               BadLocationException, IOException {
	Parser p = getParser();
	if (p == null) {
	    throw new IOException("Can't load parser");
	}
	if (offset > doc.getLength()) {
	    throw new BadLocationException("Invalid location", offset);
	}

	ParserCallback receiver = doc.getReader(offset, popDepth, pushDepth,
						insertTag);
	Boolean ignoreCharset = (Boolean)doc.getProperty
	                        ("IgnoreCharsetDirective");
	p.parse(new StringReader(html), receiver, (ignoreCharset == null) ?
		false : ignoreCharset.booleanValue());
	receiver.flush();
    }

    /**
     * Write content from a document to the given stream
     * in a format appropriate for this kind of content handler.
     * 
     * @param out  the stream to write to
     * @param doc  the source for the write
     * @param pos  the location in the document to fetch the
     *   content
     * @param len  the amount to write out
     * @exception IOException on any I/O error
     * @exception BadLocationException if pos represents an invalid
     *   location within the document
     */
    public void write(Writer out, Document doc, int pos, int len) 
	throws IOException, BadLocationException {

	if (doc instanceof HTMLDocument) {
	    HTMLWriter w = new HTMLWriter(out, (HTMLDocument)doc, pos, len);
	    w.write();
	} else if (doc instanceof StyledDocument) {
	    MinimalHTMLWriter w = new MinimalHTMLWriter(out, (StyledDocument)doc, pos, len);
	    w.write();
	} else {
	    super.write(out, doc, pos, len);
	}
    }

    /**
     * Called when the kit is being installed into the
     * a JEditorPane. 
     *
     * @param c the JEditorPane
     */
    public void install(JEditorPane c) {
	c.addMouseListener(linkHandler);
        c.addMouseMotionListener(linkHandler);
	c.addCaretListener(nextLinkAction);
	super.install(c);
        theEditor = c;
    }

    /**
     * Called when the kit is being removed from the
     * JEditorPane.  This is used to unregister any 
     * listeners that were attached.
     *
     * @param c the JEditorPane
     */
    public void deinstall(JEditorPane c) {
	c.removeMouseListener(linkHandler);
        c.removeMouseMotionListener(linkHandler);
	c.removeCaretListener(nextLinkAction);
	super.deinstall(c);
        theEditor = null;
    }

    /**
     * Default Cascading Style Sheet file that sets
     * up the tag views.
     */
    public static final String DEFAULT_CSS = "default.css";

    /**
     * Set the set of styles to be used to render the various
     * HTML elements.  These styles are specified in terms of
     * CSS specifications.  Each document produced by the kit
     * will have a copy of the sheet which it can add the 
     * document specific styles to.  By default, the StyleSheet
     * specified is shared by all HTMLEditorKit instances.
     * This should be reimplemented to provide a finer granularity
     * if desired.
     */
    public void setStyleSheet(StyleSheet s) {
        if (s == null) {
            AppContext.getAppContext().remove(DEFAULT_STYLES_KEY);
        } else {
            AppContext.getAppContext().put(DEFAULT_STYLES_KEY, s);
        }
    }

    /**
     * Get the set of styles currently being used to render the
     * HTML elements.  By default the resource specified by
     * DEFAULT_CSS gets loaded, and is shared by all HTMLEditorKit 
     * instances.
     */
    public StyleSheet getStyleSheet() {
        AppContext appContext = AppContext.getAppContext();
        StyleSheet defaultStyles = (StyleSheet) appContext.get(DEFAULT_STYLES_KEY);

	if (defaultStyles == null) {
	    defaultStyles = new StyleSheet();
            appContext.put(DEFAULT_STYLES_KEY, defaultStyles);
	    try {
		InputStream is = JavaQQHTMLEditorKit.getResourceAsStream(DEFAULT_CSS);
		Reader r = new BufferedReader(
		        new InputStreamReader(is, "ISO-8859-1"));
		defaultStyles.loadRules(r, null);
		r.close();
	    } catch (Throwable e) {
		// on error we simply have no styles... the html
		// will look mighty wrong but still function.
	    }
	}
	return defaultStyles;
    }
    
    /**
     * Fetch a resource relative to the HTMLEditorKit classfile.
     * If this is called on 1.2 the loading will occur under the
     * protection of a doPrivileged call to allow the HTMLEditorKit
     * to function when used in an applet.
     *
     * @param name the name of the resource, relative to the
     *  HTMLEditorKit class
     * @return a stream representing the resource
     */
    static InputStream getResourceAsStream(String name) {
	try {
            return ResourceLoader.getResourceAsStream(name);
	} catch (Throwable e) {
	    // If the class doesn't exist or we have some other 
	    // problem we just try to call getResourceAsStream directly.
	    return JavaQQHTMLEditorKit.class.getResourceAsStream(name);
	}
    }

    /**
     * Fetches the command list for the editor.  This is
     * the list of commands supported by the superclass
     * augmented by the collection of commands defined
     * locally for style operations.
     *
     * @return the command list
     */
    public Action[] getActions() {
	return TextAction.augmentList(super.getActions(), this.defaultActions);
    }

    /**
     * Copies the key/values in <code>element</code>s AttributeSet into
     * <code>set</code>. This does not copy component, icon, or element
     * names attributes. Subclasses may wish to refine what is and what
     * isn't copied here. But be sure to first remove all the attributes that
     * are in <code>set</code>.<p>
     * This is called anytime the caret moves over a different location.
     *
     */
    protected void createInputAttributes(Element element,
					 MutableAttributeSet set) {
	set.removeAttributes(set);
	set.addAttributes(element.getAttributes());
	set.removeAttribute(StyleConstants.ComposedTextAttribute);

	Object o = set.getAttribute(StyleConstants.NameAttribute);
	if (o instanceof HTML.Tag) {
	    HTML.Tag tag = (HTML.Tag)o;
	    // PENDING: we need a better way to express what shouldn't be
	    // copied when editing...
	    if(tag == HTML.Tag.IMG) {
		// Remove the related image attributes, src, width, height
		set.removeAttribute(HTML.Attribute.SRC);
		set.removeAttribute(HTML.Attribute.HEIGHT);
		set.removeAttribute(HTML.Attribute.WIDTH);
		set.addAttribute(StyleConstants.NameAttribute,
				 HTML.Tag.CONTENT);
	    }
	    else if (tag == HTML.Tag.HR || tag == HTML.Tag.BR) {
		// Don't copy HRs or BRs either.
		set.addAttribute(StyleConstants.NameAttribute,
				 HTML.Tag.CONTENT);
	    }
	    else if (tag == HTML.Tag.COMMENT) {
		// Don't copy COMMENTs either
		set.addAttribute(StyleConstants.NameAttribute,
				 HTML.Tag.CONTENT);
		set.removeAttribute(HTML.Attribute.COMMENT);
	    }
	    else if (tag == HTML.Tag.INPUT) {
		// or INPUT either
		set.addAttribute(StyleConstants.NameAttribute,
				 HTML.Tag.CONTENT);
		set.removeAttribute(HTML.Tag.INPUT);
	    }
	    else if (tag instanceof HTML.UnknownTag) {
		// Don't copy unknowns either:(
		set.addAttribute(StyleConstants.NameAttribute,
				 HTML.Tag.CONTENT);
		set.removeAttribute(HTML.Attribute.ENDTAG);
	    }
	}
    }

    /**
     * Gets the input attributes used for the styled 
     * editing actions.
     *
     * @return the attribute set
     */
    public MutableAttributeSet getInputAttributes() {
	if (input == null) {
	    input = getStyleSheet().addStyle(null, null);
	}
	return input;
    }

    /**
     * Sets the default cursor.
     *
     * @since 1.3
     */
    public void setDefaultCursor(Cursor cursor) {
	defaultCursor = cursor;
    }

    /**
     * Returns the default cursor.
     *
     * @since 1.3
     */
    public Cursor getDefaultCursor() {
	return defaultCursor;
    }

    /**
     * Sets the cursor to use over links.
     *
     * @since 1.3
     */
    public void setLinkCursor(Cursor cursor) {
	linkCursor = cursor;
    }

    /**
     * Returns the cursor to use over hyper links.
     * @since 1.3
     */
    public Cursor getLinkCursor() {
	return linkCursor;
    }

    /**
     * Indicates whether an html form submission is processed automatically 
     * or only <code>FormSubmitEvent</code> is fired.
     *
     * @return true  if html form submission is processed automatically,
     *         false otherwise.
     *
     * @see #setAutoFormSubmission
     * @since 1.5
     */
    public boolean isAutoFormSubmission() {
        return isAutoFormSubmission;
    }

    /**
     * Specifies if an html form submission is processed
     * automatically or only <code>FormSubmitEvent</code> is fired.
     * By default it is set to true.
     *
     * @see #isAutoFormSubmission
     * @see FormSubmitEvent
     * @since 1.5
     */
    public void setAutoFormSubmission(boolean isAuto) {
        isAutoFormSubmission = isAuto;
    }

    /**
     * Creates a copy of the editor kit.
     *
     * @return the copy
     */
    public Object clone() {
    	JavaQQHTMLEditorKit o = (JavaQQHTMLEditorKit)super.clone();
        if (o != null) {
            o.input = null;
            o.linkHandler = new LinkController();
        }
	return o;
    }

    /**
     * Fetch the parser to use for reading HTML streams.
     * This can be reimplemented to provide a different
     * parser.  The default implementation is loaded dynamically
     * to avoid the overhead of loading the default parser if
     * it's not used.  The default parser is the HotJava parser
     * using an HTML 3.2 DTD.
     */
    protected Parser getParser() {
	if (defaultParser == null) {
	    try {
                Class c = Class.forName("javax.swing.text.html.parser.ParserDelegator");
                defaultParser = (Parser) c.newInstance();
	    } catch (Throwable e) {
	    }
	}
	return defaultParser;
    }

    // ----- Accessibility support -----
    private AccessibleContext accessibleContext;

    /**
     * returns the AccessibleContext associated with this editor kit
     *
     * @return the AccessibleContext associated with this editor kit
     * @since 1.4
     */
    public AccessibleContext getAccessibleContext() {
	if (theEditor == null) {
	    return null;
	}
	if (accessibleContext == null) {
	    AccessibleHTML a = new AccessibleHTML(theEditor);
	    accessibleContext = a.getAccessibleContext();
	}
	return accessibleContext;
    }

    // --- variables ------------------------------------------

    private static final Cursor MoveCursor = Cursor.getPredefinedCursor
	                            (Cursor.HAND_CURSOR);
    private static final Cursor DefaultCursor = Cursor.getPredefinedCursor
	                            (Cursor.DEFAULT_CURSOR);

    /** Shared factory for creating HTML Views. */
    private static final ViewFactory defaultFactory = new HTMLFactory();

    MutableAttributeSet input;
    private static final Object DEFAULT_STYLES_KEY = new Object();
    private LinkController linkHandler = new LinkController();
    private static Parser defaultParser = null;
    private Cursor defaultCursor = DefaultCursor;
    private Cursor linkCursor = MoveCursor;
    private boolean isAutoFormSubmission = true;

    /**
     * Returns the extended <tt>HTMLFactory</tt> defined here.
     */
    public ViewFactory getViewFactory()
    {
        return new HTMLFactoryX();
    }

    /**
     * An extended <tt>HTMLFactory</tt> that uses the <tt>SIPCommImageView</tt>
     * to represent images and the <tt>ParagraphViewX</tt> to represent
     * paragraphs.
     */
    private class HTMLFactoryX extends HTMLFactory
        implements ViewFactory
    {
        public View create(Element elem)
        {
            View view = super.create(elem);

            if (view instanceof ParagraphView)
            {
                return new ParagraphViewX(elem);
            }
            else if (view instanceof ComponentView)
            {
                return new MyComponentView(elem);
            }else if(view instanceof ImageView){
            	return new JavaQQImageView(elem);
            }

            return view;
        }
    }

    private class MyComponentView extends ComponentView
    {
        /**
         * Creates a new ComponentView object.
         *
         * @param elem the element to decorate
         */
        public MyComponentView(Element elem)
        {
            super(elem);
        }

        /**
         * Determines the preferred span for this view along an
         * axis.  This is implemented to return the value
         * returned by Component.getPreferredSize along the
         * axis of interest.
         *
         * @param axis may be either View.X_AXIS or View.Y_AXIS
         * @return   the span the view would like to be rendered into >= 0.
         *           Typically the view is told to render into the span
         *           that is returned, although there is no guarantee.
         *           The parent may choose to resize or break the view.
         * @exception IllegalArgumentException for an invalid axis
         */
        public float getPreferredSpan(int axis)
        {
            if ((axis != X_AXIS) && (axis != Y_AXIS))
            {
                throw new IllegalArgumentException("Invalid axis: " + axis);
            }
            if (getComponent() != null)
            {
                Dimension size = getComponent().getPreferredSize();
                if (axis == View.X_AXIS)
                {
                    return container.getWidth();
                }
                else
                {
                    return size.height;
                }
            }
            return 0;
        }

        /**
         * Determines the maximum span for this view along an
         * axis.  This is implemented to return the value
         * returned by Component.getMaximumSize along the
         * axis of interest.
         *
         * @param axis may be either View.X_AXIS or View.Y_AXIS
         * @return   the span the view would like to be rendered into >= 0.
         *           Typically the view is told to render into the span
         *           that is returned, although there is no guarantee.  
         *           The parent may choose to resize or break the view.
         * @exception IllegalArgumentException for an invalid axis
         */
        public float getMaximumSpan(int axis)
        {
            if ((axis != X_AXIS) && (axis != Y_AXIS))
            {
                throw new IllegalArgumentException("Invalid axis: " + axis);
            }
            if (getComponent() != null)
            {
                Dimension size = getComponent().getMaximumSize();
                if (axis == View.X_AXIS)
                {
                    return container.getWidth();
                }
                else
                {
                    return size.height;
                }
            }
            return 0;
        }
    }

    /**
     * The <tt>ParagraphViewX</tt> is created in order to solve the following
     * problem (Bug ID: 4855207):
     * <p>
     * When a paragraph in a JTextPane has a large amount of text the
     * processing needed to layout the entire paragraph increases as the
     * paragraph grows.
     */
    static class ParagraphViewX extends ParagraphView
    {
        public ParagraphViewX(Element elem)
        {
            super(elem);
        }

        /**
         * Calculate requirements along the minor axis.  This
         * is implemented to forward the request to the logical
         * view by calling getMinimumSpan, getPreferredSpan, and
         * getMaximumSpan on it.
         */
        protected SizeRequirements calculateMinorAxisRequirements (
                int axis, SizeRequirements sizeRequirements)
        {
            if (sizeRequirements == null)
            {
                sizeRequirements = new SizeRequirements();
            }

            float pref = layoutPool.getPreferredSpan(axis);
            float min = layoutPool.getMinimumSpan(axis);

            // Don't include insets, Box.getXXXSpan will include them.
            sizeRequirements.minimum = (int)min;
            sizeRequirements.preferred
                = Math.max(sizeRequirements.minimum, (int) pref);
            sizeRequirements.maximum = Short.MAX_VALUE;
            sizeRequirements.alignment = 0.5f;
            return sizeRequirements;
        }
    }
    // --- Action implementations ------------------------------

/** The bold action identifier
*/
    public static final String	BOLD_ACTION = "html-bold-action";
/** The italic action identifier
*/
    public static final String	ITALIC_ACTION = "html-italic-action";
/** The paragraph left indent action identifier
*/
    public static final String	PARA_INDENT_LEFT = "html-para-indent-left";
/** The paragraph right indent action identifier
*/
    public static final String	PARA_INDENT_RIGHT = "html-para-indent-right";
/** The  font size increase to next value action identifier
*/
    public static final String	FONT_CHANGE_BIGGER = "html-font-bigger";
/** The font size decrease to next value action identifier
*/
    public static final String	FONT_CHANGE_SMALLER = "html-font-smaller";
/** The Color choice action identifier
     The color is passed as an argument
*/
    public static final String	COLOR_ACTION = "html-color-action";
/** The logical style choice action identifier
     The logical style is passed in as an argument
*/
    public static final String	LOGICAL_STYLE_ACTION = "html-logical-style-action";
    /**
     * Align images at the top.
     */
    public static final String	IMG_ALIGN_TOP = "html-image-align-top";

    /**
     * Align images in the middle.
     */
    public static final String	IMG_ALIGN_MIDDLE = "html-image-align-middle";

    /**
     * Align images at the bottom.
     */
    public static final String	IMG_ALIGN_BOTTOM = "html-image-align-bottom";

    /**
     * Align images at the border.
     */
    public static final String	IMG_BORDER = "html-image-border";


    /** HTML used when inserting tables. */
    private static final String INSERT_TABLE_HTML = "<table border=1><tr><td></td></tr></table>";

    /** HTML used when inserting unordered lists. */
    private static final String INSERT_UL_HTML = "<ul><li></li></ul>";

    /** HTML used when inserting ordered lists. */
    private static final String INSERT_OL_HTML = "<ol><li></li></ol>";

    /** HTML used when inserting hr. */
    private static final String INSERT_HR_HTML = "<hr>";

    /** HTML used when inserting pre. */
    private static final String INSERT_PRE_HTML = "<pre></pre>";

    private static NavigateLinkAction nextLinkAction = 
	new NavigateLinkAction("next-link-action");

    private static NavigateLinkAction previousLinkAction = 
	new NavigateLinkAction("previous-link-action");

    private static ActivateLinkAction activateLinkAction = 
	new ActivateLinkAction("activate-link-action");
	
    private static final Action[] defaultActions = {
	new InsertHTMLTextAction("InsertTable", INSERT_TABLE_HTML,
				 HTML.Tag.BODY, HTML.Tag.TABLE),
	new InsertHTMLTextAction("InsertTableRow", INSERT_TABLE_HTML,
				 HTML.Tag.TABLE, HTML.Tag.TR,
				 HTML.Tag.BODY, HTML.Tag.TABLE),
	new InsertHTMLTextAction("InsertTableDataCell", INSERT_TABLE_HTML,
				 HTML.Tag.TR, HTML.Tag.TD,
				 HTML.Tag.BODY, HTML.Tag.TABLE),
	new InsertHTMLTextAction("InsertUnorderedList", INSERT_UL_HTML,
				 HTML.Tag.BODY, HTML.Tag.UL),
	new InsertHTMLTextAction("InsertUnorderedListItem", INSERT_UL_HTML,
				 HTML.Tag.UL, HTML.Tag.LI,
				 HTML.Tag.BODY, HTML.Tag.UL),
	new InsertHTMLTextAction("InsertOrderedList", INSERT_OL_HTML,
				 HTML.Tag.BODY, HTML.Tag.OL),
	new InsertHTMLTextAction("InsertOrderedListItem", INSERT_OL_HTML,
				 HTML.Tag.OL, HTML.Tag.LI,
				 HTML.Tag.BODY, HTML.Tag.OL),
	new InsertHRAction(),
	new InsertHTMLTextAction("InsertPre", INSERT_PRE_HTML,
				 HTML.Tag.BODY, HTML.Tag.PRE),
	nextLinkAction, previousLinkAction, activateLinkAction,
    
        new BeginAction(beginAction, false),
        new BeginAction(selectionBeginAction, true)
    };


    /**
     * An abstract Action providing some convenience methods that may
     * be useful in inserting HTML into an existing document.
     * <p>NOTE: None of the convenience methods obtain a lock on the
     * document. If you have another thread modifying the text these
     * methods may have inconsistent behavior, or return the wrong thing.
     */
    public static abstract class HTMLTextAction extends StyledTextAction {
	public HTMLTextAction(String name) {
	    super(name);
	}

	/**
	 * @return HTMLDocument of <code>e</code>.
	 */
	protected HTMLDocument getHTMLDocument(JEditorPane e) {
	    Document d = e.getDocument();
	    if (d instanceof HTMLDocument) {
		return (HTMLDocument) d;
	    }
	    throw new IllegalArgumentException("document must be HTMLDocument");
	}

	/**
	 * @return HTMLEditorKit for <code>e</code>.
	 */
        protected JavaQQHTMLEditorKit getHTMLEditorKit(JEditorPane e) {
	    EditorKit k = e.getEditorKit();
	    if (k instanceof JavaQQHTMLEditorKit) {
		return (JavaQQHTMLEditorKit) k;
	    }
	    throw new IllegalArgumentException("EditorKit must be HTMLEditorKit");
	}

	/**
	 * Returns an array of the Elements that contain <code>offset</code>.
	 * The first elements corresponds to the root.
	 */
	protected Element[] getElementsAt(HTMLDocument doc, int offset) {
	    return getElementsAt(doc.getDefaultRootElement(), offset, 0);
	}

	/**
	 * Recursive method used by getElementsAt.
	 */
	private Element[] getElementsAt(Element parent, int offset,
					int depth) {
	    if (parent.isLeaf()) {
		Element[] retValue = new Element[depth + 1];
		retValue[depth] = parent;
		return retValue;
	    }
	    Element[] retValue = getElementsAt(parent.getElement
			  (parent.getElementIndex(offset)), offset, depth + 1);
	    retValue[depth] = parent;
	    return retValue;
	}

	/**
	 * Returns number of elements, starting at the deepest leaf, needed
	 * to get to an element representing <code>tag</code>. This will
	 * return -1 if no elements is found representing <code>tag</code>,
	 * or 0 if the parent of the leaf at <code>offset</code> represents
	 * <code>tag</code>.
	 */
	protected int elementCountToTag(HTMLDocument doc, int offset,
					HTML.Tag tag) {
	    int depth = -1;
	    Element e = doc.getCharacterElement(offset);
	    while (e != null && e.getAttributes().getAttribute
		   (StyleConstants.NameAttribute) != tag) {
		e = e.getParentElement();
		depth++;
	    }
	    if (e == null) {
		return -1;
	    }
	    return depth;
	}

	/**
	 * Returns the deepest element at <code>offset</code> matching
	 * <code>tag</code>.
	 */
	protected Element findElementMatchingTag(HTMLDocument doc, int offset,
						 HTML.Tag tag) {
	    Element e = doc.getDefaultRootElement();
	    Element lastMatch = null;
	    while (e != null) {
		if (e.getAttributes().getAttribute
		   (StyleConstants.NameAttribute) == tag) {
		    lastMatch = e;
		}
		e = e.getElement(e.getElementIndex(offset));
	    }
	    return lastMatch;
	}
    }


    /**
     * InsertHTMLTextAction can be used to insert an arbitrary string of HTML
     * into an existing HTML document. At least two HTML.Tags need to be
     * supplied. The first Tag, parentTag, identifies the parent in
     * the document to add the elements to. The second tag, addTag,
     * identifies the first tag that should be added to the document as
     * seen in the HTML string. One important thing to remember, is that
     * the parser is going to generate all the appropriate tags, even if
     * they aren't in the HTML string passed in.<p>
     * For example, lets say you wanted to create an action to insert
     * a table into the body. The parentTag would be HTML.Tag.BODY,
     * addTag would be HTML.Tag.TABLE, and the string could be something
     * like &lt;table&gt;&lt;tr&gt;&lt;td&gt;&lt;/td&gt;&lt;/tr&gt;&lt;/table&gt;.
     * <p>There is also an option to supply an alternate parentTag and
     * addTag. These will be checked for if there is no parentTag at
     * offset.
     */
    public static class InsertHTMLTextAction extends HTMLTextAction {
	public InsertHTMLTextAction(String name, String html,
				    HTML.Tag parentTag, HTML.Tag addTag) {
	    this(name, html, parentTag, addTag, null, null);
	}

	public InsertHTMLTextAction(String name, String html,
				    HTML.Tag parentTag,
				    HTML.Tag addTag,
				    HTML.Tag alternateParentTag,
				    HTML.Tag alternateAddTag) {
	    this(name, html, parentTag, addTag, alternateParentTag,
		 alternateAddTag, true);
	}

	/* public */
	InsertHTMLTextAction(String name, String html,
				    HTML.Tag parentTag,
				    HTML.Tag addTag,
				    HTML.Tag alternateParentTag,
				    HTML.Tag alternateAddTag,
				    boolean adjustSelection) {
	    super(name);
	    this.html = html;
	    this.parentTag = parentTag;
	    this.addTag = addTag;
	    this.alternateParentTag = alternateParentTag;
	    this.alternateAddTag = alternateAddTag;
	    this.adjustSelection = adjustSelection;
	}

	/**
	 * A cover for HTMLEditorKit.insertHTML. If an exception it
	 * thrown it is wrapped in a RuntimeException and thrown.
	 */
	protected void insertHTML(JEditorPane editor, HTMLDocument doc,
				  int offset, String html, int popDepth,
				  int pushDepth, HTML.Tag addTag) {
	    try {
		getHTMLEditorKit(editor).insertHTML(doc, offset, html,
						    popDepth, pushDepth,
						    addTag);
	    } catch (IOException ioe) {
		throw new RuntimeException("Unable to insert: " + ioe);
	    } catch (BadLocationException ble) {
		throw new RuntimeException("Unable to insert: " + ble);
	    }
	}

	/**
	 * This is invoked when inserting at a boundary. It determines
	 * the number of pops, and then the number of pushes that need
	 * to be performed, and then invokes insertHTML.
	 * @since 1.3
	 */
	protected void insertAtBoundary(JEditorPane editor, HTMLDocument doc,
					int offset, Element insertElement,
					String html, HTML.Tag parentTag,
					HTML.Tag addTag) {
	    insertAtBoundry(editor, doc, offset, insertElement, html,
			    parentTag, addTag);
	}

	/**
	 * This is invoked when inserting at a boundary. It determines
	 * the number of pops, and then the number of pushes that need
	 * to be performed, and then invokes insertHTML.
	 * @deprecated As of Java 2 platform v1.3, use insertAtBoundary
	 */
        @Deprecated
	protected void insertAtBoundry(JEditorPane editor, HTMLDocument doc,
				       int offset, Element insertElement,
				       String html, HTML.Tag parentTag,
				       HTML.Tag addTag) {
	    // Find the common parent.
	    Element e;
	    Element commonParent;
	    boolean isFirst = (offset == 0);

	    if (offset > 0 || insertElement == null) {
		e = doc.getDefaultRootElement();
		while (e != null && e.getStartOffset() != offset &&
		       !e.isLeaf()) {
		    e = e.getElement(e.getElementIndex(offset));
		}
		commonParent = (e != null) ? e.getParentElement() : null;
	    }
	    else {
		// If inserting at the origin, the common parent is the
		// insertElement.
		commonParent = insertElement;
	    }
	    if (commonParent != null) {
		// Determine how many pops to do.
		int pops = 0;
		int pushes = 0;
		if (isFirst && insertElement != null) {
		    e = commonParent;
		    while (e != null && !e.isLeaf()) {
			e = e.getElement(e.getElementIndex(offset));
			pops++;
		    }
		}
		else {
		    e = commonParent;
		    offset--;
		    while (e != null && !e.isLeaf()) {
			e = e.getElement(e.getElementIndex(offset));
			pops++;
		    }

		    // And how many pushes
		    e = commonParent;
		    offset++;
		    while (e != null && e != insertElement) {
			e = e.getElement(e.getElementIndex(offset));
			pushes++;
		    }
		}
		pops = Math.max(0, pops - 1);

		// And insert!
		insertHTML(editor, doc, offset, html, pops, pushes, addTag);
	    }
	}

	/**
	 * If there is an Element with name <code>tag</code> at
	 * <code>offset</code>, this will invoke either insertAtBoundary
	 * or <code>insertHTML</code>. This returns true if there is
	 * a match, and one of the inserts is invoked.
	 */
	/*protected*/
	boolean insertIntoTag(JEditorPane editor, HTMLDocument doc,
			      int offset, HTML.Tag tag, HTML.Tag addTag) {
	    Element e = findElementMatchingTag(doc, offset, tag);
	    if (e != null && e.getStartOffset() == offset) {
		insertAtBoundary(editor, doc, offset, e, html,
				 tag, addTag);
		return true;
	    }
	    else if (offset > 0) {
		int depth = elementCountToTag(doc, offset - 1, tag);
		if (depth != -1) {
		    insertHTML(editor, doc, offset, html, depth, 0, addTag);
		    return true;
		}
	    }
	    return false;
	}

	/**
	 * Called after an insertion to adjust the selection.
	 */
	/* protected */
	void adjustSelection(JEditorPane pane, HTMLDocument doc, 
			     int startOffset, int oldLength) {
	    int newLength = doc.getLength();
	    if (newLength != oldLength && startOffset < newLength) {
		if (startOffset > 0) {
		    String text;
		    try {
			text = doc.getText(startOffset - 1, 1);
		    } catch (BadLocationException ble) {
			text = null;
		    }
		    if (text != null && text.length() > 0 &&
			text.charAt(0) == '\n') {
			pane.select(startOffset, startOffset);
		    }
		    else {
			pane.select(startOffset + 1, startOffset + 1);
		    }
		}
		else {
		    pane.select(1, 1);
		}
	    }
	}

        /**
         * Inserts the HTML into the document.
         *
         * @param ae the event
         */
        public void actionPerformed(ActionEvent ae) {
	    JEditorPane editor = getEditor(ae);
	    if (editor != null) {
		HTMLDocument doc = getHTMLDocument(editor);
		int offset = editor.getSelectionStart();
		int length = doc.getLength();
		boolean inserted;
		// Try first choice
		if (!insertIntoTag(editor, doc, offset, parentTag, addTag) &&
		    alternateParentTag != null) {
		    // Then alternate.
		    inserted = insertIntoTag(editor, doc, offset,
					     alternateParentTag,
					     alternateAddTag);
		}
		else {
		    inserted = true;
		}
		if (adjustSelection && inserted) {
		    adjustSelection(editor, doc, offset, length);
		}
	    }
	}

	/** HTML to insert. */
	protected String html;
	/** Tag to check for in the document. */
	protected HTML.Tag parentTag;
	/** Tag in HTML to start adding tags from. */
	protected HTML.Tag addTag;
	/** Alternate Tag to check for in the document if parentTag is
	 * not found. */
	protected HTML.Tag alternateParentTag;
	/** Alternate tag in HTML to start adding tags from if parentTag
	 * is not found and alternateParentTag is found. */
	protected HTML.Tag alternateAddTag;
	/** True indicates the selection should be adjusted after an insert. */
	boolean adjustSelection;
    }


    /**
     * InsertHRAction is special, at actionPerformed time it will determine
     * the parent HTML.Tag based on the paragraph element at the selection
     * start.
     */
    static class InsertHRAction extends InsertHTMLTextAction {
	InsertHRAction() {
	    super("InsertHR", "<hr>", null, HTML.Tag.IMPLIED, null, null,
		  false);
	}

        /**
         * Inserts the HTML into the document.
         *
         * @param ae the event
         */
        public void actionPerformed(ActionEvent ae) {
	    JEditorPane editor = getEditor(ae);
	    if (editor != null) {
		HTMLDocument doc = getHTMLDocument(editor);
		int offset = editor.getSelectionStart();
		Element paragraph = doc.getParagraphElement(offset);
		if (paragraph.getParentElement() != null) {
		    parentTag = (HTML.Tag)paragraph.getParentElement().
		                  getAttributes().getAttribute
		                  (StyleConstants.NameAttribute);
		    super.actionPerformed(ae);
		}
	    }
	}
	
    }

    /*
     * Returns the object in an AttributeSet matching a key
     */
    static private Object getAttrValue(AttributeSet attr, HTML.Attribute key) {
	Enumeration names = attr.getAttributeNames();
	while (names.hasMoreElements()) {
	    Object nextKey = names.nextElement();
	    Object nextVal = attr.getAttribute(nextKey);
	    if (nextVal instanceof AttributeSet) {
		Object value = getAttrValue((AttributeSet)nextVal, key);
		if (value != null) {
		    return value;
		}
	    } else if (nextKey == key) {
		return nextVal;
	    }	
	}
	return null;
    }

    /*
     * Action to move the focus on the next or previous hypertext link 
     * or object. TODO: This method relies on support from the 
     * javax.accessibility package.  The text package should support
     * keyboard navigation of text elements directly.
     */
    static class NavigateLinkAction extends TextAction 
        implements CaretListener {

	private static int prevHypertextOffset = -1;
	private static boolean foundLink = false;
        private static FocusHighlightPainter focusPainter =
	    new FocusHighlightPainter(null);
	private Object selectionTag;
	private boolean focusBack = false;

        /*
         * Create this action with the appropriate identifier. 
         */
        public NavigateLinkAction(String actionName) {
            super(actionName);
	    if ("previous-link-action".equals(actionName)) {
		focusBack = true;
	    }
        }
	
	/**
	 * Called when the caret position is updated.
	 *
	 * @param e the caret event
	 */
	public void caretUpdate(CaretEvent e) {
	    if (foundLink) {
		foundLink = false;
		// TODO: The AccessibleContext for the editor should register
		// as a listener for CaretEvents and forward the events to
		// assistive technologies listening for such events.
		Object src = e.getSource();
		if (src instanceof JTextComponent) {
		    ((JTextComponent)src).getAccessibleContext().firePropertyChange(
                        AccessibleContext.ACCESSIBLE_HYPERTEXT_OFFSET,
		        new Integer(prevHypertextOffset),
		        new Integer(e.getDot()));
		}
	    }
	}

        /*
	 * The operation to perform when this action is triggered. 
	 */
        public void actionPerformed(ActionEvent e) {
        	System.out.println("actionPerformed");
            JTextComponent comp = getTextComponent(e);
	    if (comp == null || comp.isEditable()) {
		return;
	    }
	    Document doc = comp.getDocument();
	    if (doc == null) {
		return;
	    }
	    // TODO: Should start successive iterations from the
	    // current caret position.
	    ElementIterator ei = new ElementIterator(doc);

	    int currentOffset = comp.getCaretPosition();
	    int prevStartOffset = -1;
	    int prevEndOffset = -1;
		
	    // highlight the next link or object after the current caret position
	    Element nextElement = null;
	    while ((nextElement = ei.next()) != null) {
		String name = nextElement.getName();
		AttributeSet attr = nextElement.getAttributes();
		
		Object href = getAttrValue(attr, HTML.Attribute.HREF);
		if (!(name.equals(HTML.Tag.OBJECT.toString())) && href == null) {
		    continue;
		}
		
		int elementOffset = nextElement.getStartOffset();
		if (focusBack) {
		    if (elementOffset >= currentOffset &&
			prevStartOffset >= 0) {

			foundLink = true;
			comp.setCaretPosition(prevStartOffset);
			moveCaretPosition(comp, prevStartOffset, 
					  prevEndOffset);
			prevHypertextOffset = prevStartOffset;
			return;
		    }
		} else { // focus forward
		    if (elementOffset > currentOffset) {

			foundLink = true;
			comp.setCaretPosition(elementOffset);
			moveCaretPosition(comp, elementOffset,
					  nextElement.getEndOffset());
			prevHypertextOffset = elementOffset;
			return;
		    } 
		}
		prevStartOffset = nextElement.getStartOffset();
		prevEndOffset = nextElement.getEndOffset();
	    }
            if (focusBack && prevStartOffset >= 0) {
                foundLink = true;
                comp.setCaretPosition(prevStartOffset);
                moveCaretPosition(comp, prevStartOffset, 
                                  prevEndOffset);
                prevHypertextOffset = prevStartOffset;
                return;
            }
        }
	
	/*
	 * Moves the caret from mark to dot
	 */
	private void moveCaretPosition(JTextComponent comp, int mark, int dot) {
	    Highlighter h = comp.getHighlighter();
	    if (h != null) {
		int p0 = Math.min(dot, mark);
		int p1 = Math.max(dot, mark);
		try {
		    if (selectionTag != null) {
			h.changeHighlight(selectionTag, p0, p1);
		    } else {
			Highlighter.HighlightPainter p = focusPainter;
			selectionTag = h.addHighlight(p0, p1, p);
		    }
		} catch (BadLocationException e) {
		}
	    }
	}

	/**
	 * A highlight painter that draws a one-pixel border around
	 * the highlighted area.
	 */ 
        static class FocusHighlightPainter extends 
	    DefaultHighlighter.DefaultHighlightPainter {

	    FocusHighlightPainter(Color color) {
		super(color);
	    }
	    
	    /**
	     * Paints a portion of a highlight.
	     *
	     * @param g the graphics context
	     * @param offs0 the starting model offset >= 0
	     * @param offs1 the ending model offset >= offs1
	     * @param bounds the bounding box of the view, which is not
	     *        necessarily the region to paint.
	     * @param c the editor
	     * @param view View painting for
	     * @return region in which drawing occurred
	     */
	    public Shape paintLayer(Graphics g, int offs0, int offs1,
				    Shape bounds, JTextComponent c, View view) {
		Color color = getColor();
		
		if (color == null) {
		    g.setColor(c.getSelectionColor());
		}
		else {
		    g.setColor(color);
		}
		if (offs0 == view.getStartOffset() &&
		    offs1 == view.getEndOffset()) {
		    // Contained in view, can just use bounds.
		    Rectangle alloc;
		    if (bounds instanceof Rectangle) {
			alloc = (Rectangle)bounds;
		    }
		    else {
			alloc = bounds.getBounds();
		    }
		    g.drawRect(alloc.x, alloc.y, alloc.width - 1, alloc.height);
		    return alloc;
		}
		else {
		    // Should only render part of View.
		    try {
			// --- determine locations ---
			Shape shape = view.modelToView(offs0, Position.Bias.Forward,
						       offs1,Position.Bias.Backward,
						       bounds);
			Rectangle r = (shape instanceof Rectangle) ?
			    (Rectangle)shape : shape.getBounds();
			g.drawRect(r.x, r.y, r.width - 1, r.height);
			return r;
		    } catch (BadLocationException e) {
			// can't render
		    }
		}
		// Only if exception
		return null;
	    }
	}
    }

    /*
     * Action to activate the hypertext link that has focus. 
     * TODO: This method relies on support from the 
     * javax.accessibility package.  The text package should support
     * keyboard navigation of text elements directly.
     */
    static class ActivateLinkAction extends TextAction {

        /** 
         * Create this action with the appropriate identifier. 
         */
        public ActivateLinkAction(String actionName) {
            super(actionName);
        }

	/*
	 * activates the hyperlink at offset
	 */
	private void activateLink(String href, HTMLDocument doc, 
				  JEditorPane editor, int offset) {
	    try {
		URL page = 
		    (URL)doc.getProperty(Document.StreamDescriptionProperty);
		URL url = new URL(page, href);
		HyperlinkEvent linkEvent = new HyperlinkEvent
		    (editor, HyperlinkEvent.EventType.
		     ACTIVATED, url, url.toExternalForm(), 
		     doc.getCharacterElement(offset));
		editor.fireHyperlinkUpdate(linkEvent);
	    } catch (MalformedURLException m) {
	    }			
	}

	/*
	 * Invokes default action on the object in an element
	 */
	private void doObjectAction(JEditorPane editor, Element elem) {
		System.out.println("doObjectAction");
	    View view = getView(editor, elem);
	    if (view != null && view instanceof ObjectView) {
		Component comp = ((ObjectView)view).getComponent();
		if (comp != null && comp instanceof Accessible) {
		    AccessibleContext ac = ((Accessible)comp).getAccessibleContext();
		    if (ac != null) {
			AccessibleAction aa = ac.getAccessibleAction();
			if (aa != null) {
			    aa.doAccessibleAction(0);
			}
		    }
		}
	    }
	}
	
	/*
	 * Returns the root view for a document
	 */
	private View getRootView(JEditorPane editor) {
	    return editor.getUI().getRootView(editor);
	}

        /*
	 * Returns a view associated with an element
         */
        private View getView(JEditorPane editor, Element elem) {
            Object lock = lock(editor);
            try {
                View rootView = getRootView(editor);
                int start = elem.getStartOffset();
                if (rootView != null) {
                    return getView(rootView, elem, start);
                }
                return null;
            } finally {
                unlock(lock);
            }
        }

	private View getView(View parent, Element elem, int start) {
            if (parent.getElement() == elem) {
                return parent;
            }
            int index = parent.getViewIndex(start, Position.Bias.Forward);
	    
            if (index != -1 && index < parent.getViewCount()) {
                return getView(parent.getView(index), elem, start);
            }
            return null;
        }

	/*
	 * If possible acquires a lock on the Document.  If a lock has been
	 * obtained a key will be retured that should be passed to
	 * <code>unlock</code>.
	 */
	private Object lock(JEditorPane editor) {
	    Document document = editor.getDocument();
	    
	    if (document instanceof AbstractDocument) {
		((AbstractDocument)document).readLock();
		return document;
	    }
	    return null;
	}
	
	/*
	 * Releases a lock previously obtained via <code>lock</code>.
	 */
	private void unlock(Object key) {
	    if (key != null) {
		((AbstractDocument)key).readUnlock();
	    }
	}

        /*
	 * The operation to perform when this action is triggered. 
	 */
        public void actionPerformed(ActionEvent e) {

            JTextComponent c = getTextComponent(e);
	    if (c.isEditable() || !(c instanceof JEditorPane)) {
		return;
	    }
	    JEditorPane editor = (JEditorPane)c;
	    
	    Document d = editor.getDocument();
	    if (d == null || !(d instanceof HTMLDocument)) {
		return;
	    }
	    HTMLDocument doc = (HTMLDocument)d;

	    ElementIterator ei = new ElementIterator(doc);
	    int currentOffset = editor.getCaretPosition();

	    // invoke the next link or object action
	    String urlString = null;
	    String objString = null;
	    Element currentElement = null;
	    while ((currentElement = ei.next()) != null) {
		String name = currentElement.getName();
		AttributeSet attr = currentElement.getAttributes();
		
		Object href = getAttrValue(attr, HTML.Attribute.HREF);
		if (href != null) {
		    if (currentOffset >= currentElement.getStartOffset() &&
			currentOffset <= currentElement.getEndOffset()) {
			
			activateLink((String)href, doc, editor, currentOffset);
			return;
		    }
		} else if (name.equals(HTML.Tag.OBJECT.toString())) {
		    Object obj = getAttrValue(attr, HTML.Attribute.CLASSID);
		    if (obj != null) {
			if (currentOffset >= currentElement.getStartOffset() &&
			    currentOffset <= currentElement.getEndOffset()) {
			    
			    doObjectAction(editor, currentElement);
			    return;
			}
		    }
		}
	    }
	}
    }

    private static int getBodyElementStart(JTextComponent comp) {
        Element rootElement = comp.getDocument().getRootElements()[0];
        for (int i = 0; i < rootElement.getElementCount(); i++) {
            Element currElement = rootElement.getElement(i); 
            if("body".equals(currElement.getName())) {
                return currElement.getStartOffset();
            }
        }
        return 0;
    }
    
    /*
     * Move the caret to the beginning of the document.
     * @see DefaultEditorKit#beginAction
     * @see HTMLEditorKit#getActions
     */
    
    static class BeginAction extends TextAction {

        /* Create this object with the appropriate identifier. */
        BeginAction(String nm, boolean select) {
            super(nm);
            this.select = select;
        }

        /** The operation to perform when this action is triggered. */
        public void actionPerformed(ActionEvent e) {
        	System.out.println("BeginAction");
            JTextComponent target = getTextComponent(e);
            int bodyStart = getBodyElementStart(target);
            
            if (target != null) {
                if (select) {
                    target.moveCaretPosition(bodyStart);
                } else {
                    target.setCaretPosition(bodyStart);
                }
            }
        }

        private boolean select;
    }
}
